Multiplying machine



Oct. 4, 1938. T. E. TORKELSON MULTIPLYING MACHINE Filed Dec. 20, 1952 12 Sheets-Sheet 1 gINVN-I'ORZ AT'TORNEY 'FIGJ.

Oct. 4, 1938. T. E. TORKELSON MULTIPLYING MACHINE 12 Sheets-$heet 2 Filed Dec. 20, 1932 J gIyENTOR Oct. 4, 1938. T. E. TORKELSON 2,131,903

MULTIPLYING MACHINE Filed Dec. 20, 1932 12 Sheets-Sheet s AT'TORNEY It; INVENTOR Oct. 4, 1938. T. E, TORKELSON 2,131,908

MULTIPLYING MACHINE l2 Sheets-Shet 4 Filed Dec. 20, 1932 ATTORNEY- Oct. 4, 11938. E, TORKELSON 2,131,908

MULTIPLYING MACHINE Filed Dec. 20, 1932 12 Sheets-Sheet 5 llllllfllmgm 46 Minn MWAZZW A'TTQRNEY IHlllllllllll llllllllllll! '-|||||||||i: 6

O 1938. T. E. TORKELSON 2,131,908

MULTIPLYING MACHINE Filed Dec. 20, 1952 12 Sheets-Sheet 6 g lflyToR- 'ATTORNEY- Oct. 4, 1938. T. E. TORKELSON 2,131,908

MULTIPLYING MACHINE Filed Dec. 20, 1932 12 Sheets-Sheet 7 ATTORNEY- Oct. 4, 1938. T. E. TORKELSON MULTIPLYINGMACHINE Filed Dec.

20, 1952 12 Sheets-Sheet 8 FIG,15..

2222, BY Mf -2Y- Oct. 4, 1938., E TQRKELSON I 2,13L908 MULTIPLYING- MACHINE Filed Dec. 20, 1932 12 Sheets-Sheet 9 a a INVENTZR- ATTORNEY- Oct. 4, 1938. T. E. ToRkELsoN 2,131,908

MULTIPLYING MACHINE Filed Dec. 20, 1932 12 Sheets-Sheet 10 J 2 g; g vEgToR- M ATI'ORN EY- Oct. 4, 1938. E, TORKELSON 2,131,908

MULTIPLYING MACHINE Filed Dec. 20; 1932 12 Sheets-Sheet 11 INVENTQZ- 3 MM ATTORN EY- 1938. i T. E. TORKELSON 2,131,908

MULTIPLYING MACHINE .Filed Dec. 20, 1932 12 Sheets-Sheet l2 a g INVENTOR- ATTORNEY- Patented Oct. 4, 1938 UNITED STATES PATENT OFFICE MULTIPLYING MACHINE poration of New York Application December 20, 1932, Serial No. 048,036

1 Claim.

This invention relates to improvements in calculating machines and, more particularly, the invention is directed to improvements in multiplying machines.

One of the objects of the present invention is to provide a multiplying machine which is capable of effecting computations at a very rapid rate.

A further object of the invention is to provide an improved multiplying machine adapted to effect multiplications of factors involving multi-denominational amounts by utilizing timed impulses derived from multiplying commutators.

At the present time it is the common practice in multiplying machines to multiply each denominational order of the multiplicand by one of the digits of the multiplier and the results (i. e., the partial products) are separately assembled until the multiplicand has been separately multiplied by each of the digits of the multiplier. Following this, the partial products are assembled to form the complete product of the multiplicand and multiplier. The operation of multiplication according to this plan necessitates separate accumulating or storing devices to separately assemble the different partial products and further mechanism for assembling the partial products to complete the problem. According to the present invention, it is proposed to provide a single accumulator or storing device into which all of the partial products may be entered, thus providing a simpler and more compact machine and eliminating the mechanism necessary for the final assembling of the partial products.

The machine proceeds in operation by establishing a progression correlated to one of the factors and constituting all of the results which can come from that factor taken with any other possible digits in the notation and in the remaining factor. Thus, if 8 were the multiplier, the machine would form a progression as follows: 8--l624 32-4048--5664-72. These amounts, it will be noted, are an arithmetical progression based upon 8 and in their entirety constitute all the results which might be obtained by multiplying any of the digits of the tens notation by 8.

Having established such progression wherein the denominational values of the terms are still undetermined, a selection is made from the terms of this progression. It is to be further noted that plicand entry then acts to select out of the already Considering the example 6764 8=54112 by way of illustration, the following terms of the 8 progression will be selected: 3248 and 56. These selected terms are the ones representative of multiplying 4 and 8, 6 and 8, and 7 and 8.

In the above computation, the multiplication of 6 and 8 occurs twice. Accordingly, the multiplicand makes a selection of the 48 term from the progression and uses it twice and in doing this, so effects an allocation of the denominational order values of 48 to properly enter such values into the receiving device. One of the 48's has a value allocated to it of 48000 and the other a value of 480. Up to the point where the 48 was selected by the multiplicand it had an abstract value of 48 and no denominational value whatever. The multiplicand similarly allocates values to the other selected terms. Thus, 56 has an allocated denominational value of 5600 and 32 remains as 32. These terms are now assembled in the receiving device thus:

The machine, furthermore, in creating and coordinating the progression, proceeds by first potentially creating all of the digit values of a notation or representations thereof wholly without regard to their denominational order or arrangement with respect to any problem that the machine is to compute. Thus, with the computations involving a tens system of notation, the machine will create transient representations of the different digits 1 to 9. It is these transient representations that the machine coordinates into a progression in accordance with one of the factors.

The multiplicand device in selecting and allocating denominational values acts so that the transmission of the various representations from the progression into the receiving device takes place concurrently. In this way, operating time is saved.

Summarizing briefly, the machine starts with a transient representation of digits, coordinates them into a transient progression, and selects and allocates from said progression. The result is obtained only after the completion of the computing cycle and upon the transfer of the representation into the receiving device. are made potentially available and are developed by the computing cycle by coordination, the selec- The ultimate results tion and denominational allocation to be interpretable upon their entry into the receiving device. By virtue of this novel law of operation, the machine is relatively simple in construction and expeditiously handles complex problems.

A further object of the invention resides in the provision of a machine which will effect such computations more rapidly than heretofore.

A further object resides in the provision of a machine which will effect such a class of computations with simpler mechanism than has been known heretofore.

A further object of the present invention resides in the provision of a novel impulse emitting and coordinating means whereby single emitting devices may be used for emitting the impulses which are to ultimately designate product amounts when received by the receiving device, which impulses are wholly uncoordinated to denominational orders, and to further provide for the denominational coordination of such impulses as they pass to the receiving device.

Before describing the detailed construction and operation of the machine, it may be stated that use is made of a single register for receiving and accumulating all the partial products of the machine as they are computed and will therefore indicate the complete product upon completion of the last computing operation.

The register employs differential gearing which as here shown, is adapted to be controlled by differentially timed impulses. The impulse emitting means are timed and coordinated to the cycle of the register, such impulse emitting means being driven concurrently and synchronously with the register. The factor entry means are intended to control the flow of impulses from the emitters to the receiving means or register.

According to the preferred form of the invention, a separate impulse emitting means is provided for partial products known as left hand partial products and another for the so-called right hand partial products. The emitters are arranged to operate in succession to first enter the left hand partial products derived from the multiplication of the first digit in the multiplier by the multiplicand into the register and then to enter the right hand partial product of such multiplication into the same register. Following this, the left and right hand partial products of the remaining orders of the multiplier are successively entered into the register. The register itself is provided with novel transfer mechanism which, by virtue of the differential construction of the register, will effect transfer operations during that portion of the cycle in which entries are being efiected. This permits the construction of a register having an operating cycle not longer than the period required to enter items therein from the emitters. This in turn permits shorter operating cycles than has heretofore been possible in multiplying machines, with a resultant higher operating speed of the machine as a whole.

In accordance with a modified form of the invention, the difierential register may be of a somewhat modified form to permit the concurrent entry of left hand and right hand partial products therein so that in the single cycle of operation, a complete entry will be made of the true product obtained by the multiplication of the entire multiplicand by one of the digits of the multiplier. With this type of construction, the number of computing cycles will be exactly equal to the number of digits in the multiplier factor.

Various other objects and advantages of the invention will be obvious from the following particular discription of two forms of mechanism embodying the invention or from an inspection of the accompanying drawings; and the invention also constitutes certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the drawings:

Figs. 1, la and 1b, placed side by side in the order mentioned, comprise a complete circuit diagram of the preferred form of the invention.

Fig. 2 is an example of a multiplying computation as performed by the machine and illustrates the successive steps of operation of the machine which are required to obtain a product.

Fig. 3 is a diagrammatic view showing the general arrangement of the several units of the machine.

Fig. 41s an enlarged detail view of the register or accumulating device.

Fig. 5 is a sectional view taken on lines 55 of Fig. 4.

Fig. 6 is a sectional view taken on lines 15-45 of Fig. 4.

Fig. '7 is a sectional view taken on lines 1--1 of Fig. 4.

Fig. 8 is a sectional view taken on lines 8-8 of Fig. 4.

Fig. 9 is a detail of the differential accumulator construction, the section being taken on lines 99 of Fig. 8.

Fig. 10 is a detail of the main operating clutch of the device, the section being taken substantially along the lines Ill-49 of Fig. 3.

Fig. 11 is a detail of a fragment of a keyboard used in setting up the multiplicand.

Fig. 12 is a detail of the column selecting device, the detail being taken substantially along the lines l2-I2 of Fig. 3.

Fig. 13 is a sectional view of one of the impulse emitting commutators, the section being taken substantially along the lines I3-l3 of Fig. 3.

Fig. 14 is a sectional view taken along lines I l-I4 of Fig. 13.

Fig. 15 is a sectional view of a modified form of the invention.

Fig. 16 is a section taken substantially along lines |6l6 of Fig. 15.

Figs. 1'7 and 17a, taken together, comprise part of a circuit diagram of the modified form of the invention showing the arrangement which permits the simultaneous entry of the several partial products into the single registering device.

Fig. 18 is a further detail of the driving mechanism of the modification.

The machine comprises several separate sections which are coordinated for conjoint operation. For convenience in description, each of these sections or assemblies will be separately explained.

Factor entry devices In general, the machine may be stated to comprise factor entry sections, one for the multiplicand, and one for the multiplier. While the invention is not limited to the particular form of factor entry means herein shown, such factor entry means as here disclosed comprise a multicolumnar key type of entry means for the multiplicand and a single column of keys for the multiplier. In Fig. 1, the column of multiplier keys is generally designated MP and the bank of multiplicand keysin Fig. 1b is designated MC. Fig. 11 shows the details of the multiplicand keys In, each of which has a conducting strip II secured to and insulated from itslower end, which,

upon depression, is adapted to engage contact elements I2 arranged as shown. A latching plate I3 is provided, which is adapted to hold a selected key in depressed position in accordance with the ,interlocks (not shown) may be provided to prevent depression of more than one key at a time.

Latching plate |3a is provided to hold the keys depressed until the multiplying operations they control are completed when a magnet lla is energized to release the same and permit depres- I sion ofthe next key. The control for magnet Ha will be more fully explained hereinafter. It is therefore apparent that a multi digit multiplicand and a digit of a multiplier are separately set up on their respective keyboards MP and M0 to close the selected contacts I, H and ||2a and that the setting of the multiplicand keys will be maintained until they are released by moving the latching plates |3 either separately or collectively.

For convenience of illustration, the multiplicand key bank has been limited to four columns and the machine will be described as a fixed cycle machine; that is, a definite predetermined number of operating cycles will take place for each multiplying operation to be performed, although it is to be understood that the capacity ofthe device may be readily altered without departure from the spirit of the invention.

' Multiplying commutators The machine further comprises a multiplyingcommutator section which is shown in Fig. 1a, and which comprises nine individual commutator assemblies in which the commutators are stationary and internal brushes are provided to cooperate with the inner surfaces of the commutators. This multiplying commutator section takes the factors as derived from the keyboards and multiplies them and controls the accumulation of partial products into the accumulating means.

Referring to Figs. 13 and 14, each commutator comprises a central common conducting ring M, a lower or right hand emitting section I5, and an upper or left hand emitting section I6. A brush ll carried, by an arm I8 secured upon a shaft l9a is adapted to cooperate with the sections I4, l5 -and I6 during the rotation of the shaft Na.

Accumulator The next general section of the machine comprises the accumulator or register shown in Figs.

4 to 8 and in the upper left handv portion of mounted. The gear 20 therefore makes two revolutions for each revolution of the commutator brushes ll. Adjacent to gear 20 is a gear 2| which is adapted to be coupled for driving engagement with gear 2|) under control of a magnet 22. Energization of magnet 22 will attract its armature 23 and will permit clockwise rotation, as viewed in Figs. 5 and'6, of arm 24 which carries a pinion 25 at its upper end. Pinion 25 is adapted to engage gears 20 and 2| simultaneously so that the former drives the latter during the period that pinion 25 is in engagement therewith. Gear 20 carries a pin 26 which is adapted to strike an extension 21 on arm 24 to disengage the parts and restore arm 26 to its latched position. This restoring action takes place at the end of a cycle of shaft l9 and the angular displacement of the gear 2| will accordingly be dependent upon the time of energization of magnet 22. The operation of the accumulating mechanism is in accordance with a ten point cycle'so that if magnet 22 is energized six points before pin 26 strikes extension 21, an entry of six will accordingly be made on the gear 2|. In-

tegral with gear 2| are internal teeth 28 meshing with a. differential pinion 29 which is mounted upon differential gear 30. The differential gear 30 carries a second pinion 3| meshing with pinion 29 and also in engagement with an internal gear 32 Fig. 9. The gear 32 is also provided with teeth on its outer circumference which are in engagement with carrying pinion 33 carried by a rod 34 which rod has a.second carrying pinion 35 at its opposite end.

This second carrying pinion is adapted to cooperate with a mutilated gear 36 which is integral with the differential gear 38 of the next lower denominational order.

In accordance with the well known manner of operation of a differential entering device, if

gear 32 is restrainedv against rotation, turning of 1 gears 2| and teeth 28 will drive the differential portional to the sum of the-.movement of the gears 32 and 28.

In Fig. 6, a spring pressed arm 31 is provided which normally restrains gear 2| against rotation while the parts are in the position shown and which releases gear 2| when the latter is being driven. In Fig. '7 the teeth on the gear 36 are so located that they drive the pinion 35 as the gears 30 and 36' pass through the zero position, thereby also turning gear 33 to advance the next higher denominational order gear 32 a distance equivalent to the entry of one. By virtue of the arrangement of the accumulator just described, this carrying entry of one may be effected while an entry is being made into the same order under control of the magnet 22. This arrangement makes it unnecessary to provide additional index points in the operating cycle of the machine to obtain time for performing carrying operations after each entry as has heretofore been the practice, thus permitting shorter machine cycles and the consequent more rapid operation of the entire apparatus. A detenting pawl 31a engages gear 32 to hold the same impo'sitively.

Printing mechanism As shown in Figs. 4 and 8, each differential gear 30 is adapted to drive a gear 40, each of which is connected to one end of one of a nest of sleeves 4|, which, at their opposite ends, carry printing wheels 42 above which any suitable record material 43 may be placed and upon which may be printed the result of the computation; namely, the product of the factors set up on the keyboards MC and MP.

Provision is made in the form of a printing hammer 44 and an armature latch 45, which latch is adapted to release the hammer 44 upon energization of magnet 46. This energization is arranged to take place at the completion of the computation of the product so that an impression thereof may be taken upon such completion. Suitable means (not shown) may be provided for relatching hammer 44.

Machine drive Referring to Fig. 3, the motive power for operating the machine is provided by the motor M which drives a gear 41 loose upon shaft 19a and having integral therewith a clutch driving element 49 which is also shown in Fig. 10. Secured upon shaft I9a is a clutch disk 50 integral with a gear 5|. The disk 50 carries the usual spring pressed clutching pawl 52 held in the position shown in Fig. by the latching armature 53 of a clutch magnet 54. This clutch device is of the usual one-revolution type and momentary energization of magnet 54 will release the pawl 52 for engagement with driving member 49 whereupon the shaft Na and gear 5| will be driven for one complete revolution, the parts de-clutching automatically at the end of such revolution.

The machine is arranged to effect a complete multiplication of two four place factors during four revolutions of shaft Ho and to effect the printing of the product at the end of the fourth revolution. Gear 5| is adapted to drive shaft 48 through an idler gear 55 and a gear 56 carried by shaft 48, the ratio being such that shaft l9 makes four revolutions for one revolution of shaft 48.

Referring to Fig. 1, the motor M receives current immediately upon closure of switch S thus causing the driving element of the one revolution clutch to operate. Clutch magnet 54 has a pair of contacts 51 in series therewith which is adapted to be closed upon depression of a bar 58.

Depression of any key i 0a will close contacts 51 to complete the circuit through magnet 54 and shaft i9a. will consequently make one revolution during which the product of the multiplicand and the digit repres nted by the depressed key illa will be entered in the accumulator in a manner to be described. Toward the end of this revolution of shaft No, a cam 59 carried thereby momentarily closes a pair of contacts 60 to energize latch releasing magnet Ila so that key Illa may be released. Depression of another key Illa will repeat the cycle of operations and if the key depression follows closely upon the action of latch releasing magnet Ha the succeeding cycle of shaft I911. will continue without interruption, since under such conditions the timing of the parts will permit reclosure of contacts 51 and reenergization of magnet 54 before shaft I9a is declutched.

Column shift mechanism In Figs. la and 12 are shown a plurality of commutators 68 having cooperating brushes 69 and collector rings 10. These commutators are similar in structure to the commutators l5 and I6 and their brushes ,are carried by the shaft 48. The function of the commutators 68 and brushes 69 is to-allocate the partial products to the proper denominational orders of the accumulating device.

It will be noted that the commutators are all identical in structure, each having five separate conducting segments interconnected as shown in the circuit diagram.

General operation Before tracing the detailed operation of the machine, a general explanation of the manner of assembling the partial products to produce the product will be made in connection with Fig. 2. Here it is proposed to multiply 2697 by 3485.

It has been pointed out above that for a complete multiplying operation of two four-place factors shaft 48 will make one revolution, shaft i9a will make four revolutions and shaft I9 will make eight revolutions.

During the first two cycles of shaft IS, the multiplicand is separately multiplied'by the units digit of the multiplier, that is, 5, and the resulting right hand partial product of 55 is entered into the units and tens orders of the accumulating device, the 5 in the units position being the right hand figure derived from the multiplication of 5 times 7 or 35 and the 5 in the tens position being the right hand figure of the result of the multiplication of 5 times 9 or 45. 5 times 6 being 30, producing a right hand or units figure of zero will, of course, effect no significant entry; similarly, for the product of 5 times 2. These entries are made in the first cycle of shaft l9. During the second cycle, the left hand figures of the separate computations are entered into the accumulating device and the relationship of the circuits to the accumulator is varied so that the entries are made with the tens order receiving the lowest denominational order of this partial product.

In the third and fourth cycles, the right and left hand partial products of the result of multiplying the multiplicand by 8, the tens digit of the multiplier, are successively entered as indicated, the tens partial product being entered one position higher than the units. It will be understood that as these entries are successively made to the various orders of the accumulator, the carrying operations involved when the accumulator gears or wheels pass through zero or ten position will be automatically eifected. During the remaining cycles, the several partial products as indicated will be entered into the accumulating device in the denominational orders as represented in Fig. 2, so that at the completion of the eighth cycle of shaft i9 or the single revolution of shaft 48, the amount 9399045 will stand on the accumulating device and on the printing wheels and the printing hammer will have been tripped to transfer this reading to the record material.

The accumulating device may be provided with resetting mechanism to restore the unit to zero position but for the sake of simplicity, this mechanism has been omitted from the drawings. If it is desired to reset the accumulating device without the incorporation of additional mechanism, such operation may be readily effected by manually turning the printing wheels 42 so that each indicates zero. By virtue of their gear connection with the diflerential gears 30, the latter will be similarly displaced.

be explained in connection with the circuit diagram in Figs. 1, 1a and lb and in accordance with the problem of Fig. 2. The keys of the multiplicand keyboard MC-will be set and latched to represent the value 2697 and these keys will close their corresponding contact devices II, I2. The machine is now ready to commence multiplying operations, switch S having previously been closed. The 5 key Ia, in accordance with the units digit of the multiplier is then depressed and latched, closing contacts 51, which as explained above will initiate a revolution of shaft I9a and an accompanying two revolutions of shaft I9 and a quarter revolution of shaft 48. In the diagram,

groups of wires and segments are designated with a single reference numeral identifying the group and specific wires or segments are identified by the group number followed by 9. numeral; for example, 'I89 indicates the ninth wire of the group of wires generally designated I8 and I--5 indicates the 5 segment of the group generally designated I5.

Brushes I1 (Fig. 1a) will proceed to traverse the segments I5 of the multiplying commutators and when the brush I! of the 7 position commutator is at the 5 position segment I5, specifically Iii-5, a circuit will be completed which may be traced as follows: From line I5 (Fig. 1), wire it, wire IT in the 5 multiplier key position, lowermost contact I2a5, wire I8-9 of a group of fourteen wires generally designated I8 (see also Fig-1a), segment Iii-5 of the 7 connector brushes I'I, corresponding collector ring I4, wire 19-! of a group of wires I9 (see also Fig. 11)), contacts II, I2 of the '"lfkey I0 in the units order of the multiplicand, wire 80--I (Fig. 1a),

collector ring I0 of the right hand commutator 68, brushes 69, segment 68a, wire 8|, units order accumulator magnet '22, wire 82 (Fig. 1) to other side ofline' 83.

This circuit has been shown in heavy lines-to facilitate the tracing of its path. The completion of the circuit at the 5" time in the cycle of the accumulator will cause the entry of a 5 in the units order of the accumulator.

A second circuit will be concurrently completed through a similarly traceable circuit to enter a 5 in the tens order magnet 22 as the result of the multiplication of 5 and the tens digit "9 of the multiplicand. This circuit will be substantially the same as that traced, flowing along wire 18-9 (Fig. 1a) and branching to continue to segment Iii-5 of the 9 multiplying commutator, thence to wire 19--9 (Fig. 15), contacts I I, I2 of the 9 key in the tens order of the multiplicand wire 80--2 (Fig. la), commutator 50, segment to wire 84 and the tens order magnet 22.

Thus at the end of the first half revolution of shaft Illa the amount 55 as indicated in the first cycle line of Fig. 2 will have been entered as indicated. During this cycle brushes 69 (Fig. 1a)

traversed segments 68a and during the next half revolution of shaft I9a these brushes will traverse part of segments 6% to provide the denominational order column shift as will be clear from the circuits to be presently traced.

During this following operation brushes I?! will traverse the upper segments I6 and circuits will be completed in accordance with the right hand components of the multiplaction of 5 and 2697.

.Taking, for example, 5 times 7, when brush II reaches the segment Iii-3 of the '7 multiplying commutator the following circuit will become effective: From line I5 (Fig. 1), wire I6, wire, ll

in the 5 key position, closed contact I2w-3, wire 85, wire 86-I of a group 86 (Fig. 1a), segment I6 3,' brushes II, collector ring I4, wire I9I (Fig. 15), contacts II, I2 of the 7 position in the units column of the multiplicand, wire 80--I (Fig. la) collector ring I0, brushes v(i9, segment 68b, wire 84, tens order magnet 22, wire 82 to line 83 as before.

During this same half revolution of shaft I9a parallel circuits willcause entry of a l, a 4 and another 3 in other denominational orders of the accumulator in accordance with the 2nd cycle line of Fig. 2, so that at the completion of a single revolution of shaft I9a the complete prod uct of 5 and 2697 will be recorded.

With the 5 multiplier key I00. released at the end of the cycle and the key 8 thereafter depressed in accordance with the tens digit of the multiplier, the shaft Illa will enter upon a second revolution during the first half of which the amount shown on the 3rd cycle line of Fig. 2 will be entered and during the second half, the amount represented on the 4th cycle line will be entered. Subsequent depression of the 4 multiplier key and then the 3 multiplier key will add further amounts in the positions shown, commutators 68 controlling the selection of the denominational orders into which the various amounts are to be entered.

At the end of the last multiplying operation, which is coincident with the completion of a full revolution of shaft 48, a cam 81 on this shaft will momentarily close contacts 88' to energize print magnet 46 to transfer the reading on the accumulator to an appropriate record. Resetting may then be effected as outlined above. It will be noted that each key l0a (Fig. 1) closes a plu rality of contacts I 20., some of which complete the 'LH partial products circuits and the others comcuits for 5X5 only and the lowermost completes the RH circuits for 5x1, X3, X7, and X9.

Modification A modified form of the invention is shown in Figs. 15 and 16 by means of which the partial products associated with each digit of the multiplier may be simultaneously entered into the receiving device. Each denominational order thereof comprises a differential gear I00 having differential pinions IOI which are driven by gears 102 and I03 in the well known manner. Gear I03 is in engagement with a gear I04 driven from a gear I05 on shaft I9 through the 'medium of connecting pinion I06 which may be brought into action under the influence of magnet I0'IL in a manner already explained.

Gear I02 is in engagement with a gear Illta driven from a gear I05a on shaft I9" throu the I through pinions H2 from mutilated gear 3 of the next lower order for carrying purposes in exactly the same manner as gear 32 of the preferred form.

It therefore becomes evident that with the construction just described, two entries may be concurrently made on gear I and the combined result impressed upon gear 0 to be further transferred to gear I08. Digits to be carried are concurrently entered on gear I08 so that the latter gears ultimately represent the product of the multiplication performed. Printing of the product may be effected as in the preferred form through gears H4 and type wheels 5.

Figs. 1, 17 and 17a placed side by side with Fig. 1 on the left and Fig. 17a on the right, comprise a complete circuit diagram of the modified form of the device which will now be described. The same problem is chosen for purposes of explanation as was used in explaining the preferred form and the same procedure in setting up the successive digits of the multiplier is followed. Each key of the multiplicand keyboard is provided with-two contact devices ll, I2, and ii", i2", the former for controlling the left hand partial product circuits and the latter for the right hand partial product circuits. The contacts are separately grouped in Fig. 17a to avoid complications in the wiring arrangement and to render the separate circuits more readily traceable.

The multiplying commutators (Fig. 17) are provided with double brushes I1 and Ha and the corresponding collector ring is comprised of two separate strips l4 and Ila. This arrangement permits both upper and lower groups of segments of the multiplying commutator to be read during a half revolution of the brushes. In Fig. 18 is shown the modified gearing arrangement between the various elements. Shaft l9'a upon which the multiplying commutators are mounted is driven from clutch element 49' under control of a. half revolution clutch controlled by magnet 54' which is controlled identically as magnet 54 in the preferred form. It follows then, that four half revolutions of shaft l9'a will be enough to take care of a four place multiplier. Since shaft 48' which carries the column shift commutators is to make but a single revolution for a-complete problem it is geared as shown with a two to one drive from shaft l9a. Shafts l9 and IQ" of the accumulator are geared to make a complete revolution for a half revolution of shaft l9a'.

.Returning now to Figs. 1, 17 and 17a, the operations involved in the multiplication of the multiplicand by the first or units digit of the multiplier will now be traced from which the steps involved in the remaining cycles will be apparent. With the multiplicand 2697 set up up on the keyboard, depression of the 5 multiplier key will energize magnet 54' to initiate the first half revolution of shaft l9'a.

As brush Ila (Fig. 17) contacts segment l55 a circuit may be traced as follows: From line 15 (Fig. 1), wire 16, wire 11, contact l2a5, wire 18-9, (Fig. 17) segment l5'-5, brush Ila, collector strip Ma, wire 19a--1 of group of wires 1911 (Fig. 17a) contacts ll", l2" in the 7 position of the units order of the multiplicand, wire Bria-l, collector ring 1011, brush 69a, segment 68", wire am to the units order accumulator magnet IOTR, wire 82, back to line 83. This will cause the entry of a 5 in the units order of the accumulator.

During the same half revolution, when brush ll' (Fig. 17) contacts segment l63, a parallel circuit may be traced as follows: From line 15 (Fig. 1), wire 16, wire 11, contact |2a 3, wire 86--l (Fig. 17), segment l6-3, brush ll', collector strip l4, wire I9'| of a group of wires I9 (Fig. 170.), contacts Ii, l2 in the "7 position of the units order of the multiplicand wire 80'l, collector ring brush 69', segment 68', wire 8! to tens order accumulator magnet IO'IL, wire 82, to line 83.

Also, during this same half revolution, parallel circuits will be completed through the other order of the multiplicand keys to enter a 5 in the tens order magnet HR and 1, 3.and 4 in the ten thousands, thousands, and hundreds order magnets lOlL, so that at the completion of the half revolution, the complete product of 5" and 2697; namely, 13485, will have been entered into the single accumulator.

Depression at this time of the key of the multiplier representing the tens digit of the multiplier will be followed by appropriate column shifting and entry of the product of 8 and 2697 into the accumulator.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to two modifications, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated and in their operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claim.

What is claimed is:

In a multiplying machine, a plurality of multiplying commutator devices, one for each of the digits of a notation and each being arranged to emit impulses representative of the product of one of said digits times all the digits, a plurality of multiplicand keys settable to represent a multidenominational multiplicand, a digit line connecting each digit representing commutator device to the keys corresponding to the same digit,

.a plurality of multiplier keys, one for each significant digit, a set of pairs of contacts for each multiplier key, a set of eight digit representing lines connecting said commutator devices to one, two or three pairs of contacts of each key, a second set of fourteen digit representing lines connecting said commutator devices to one, two or three other pairs of contacts of each key, the maximum number of pairs of contacts in any set being six, and means controlled upon operation of any multiplier key for eifecting an operation of said commutator devices to complete a circuit through one of the pairs of contacts, the set of eight lines and the first named set of lines in accordance with the left hand partial products and a circuit through another of the pairs of contacts, the set of fourteen lines and the first named set of ines in accordance with the right hand partial products of the multiplier digit and the amount set on the multiplicand keys.

TORKEL E. TORKELSON. 

